1. Field of the Invention
The present invention relates to electrical connectors, and more specifically, to filtered and shielded electrical connectors in which discrete capacitors are positioned in the connector between contact terminals and ground. This invention also relates to other electrical connectors in which discrete electrical components are positioned in the connector. This invention is also related to the use of conventional chip components, such as surface mount capacitors, resistors, inductors, shorting links, fuses, diodes, light emitting diodes and other similar components, in electrical connectors. This invention is also related to the use of a resilient conductive member, such as an elastomeric member with an outer conductive surface, to connect components positioned in the connector to corresponding contact terminals and to a grounding surface or a shield.
2. Description of the Prior Art
Electrical connectors in which discrete electrical components such as capacitors, resistors, inductors, shorting links, fuses, diodes, light emitting diodes and other similar components, have become increasingly common. Filtered electrical connectors employing capacitors or other filtering elements are used to filter electromagnetic interference and radio frequency interference in noisy environments. One common method for including filtering in electrical connectors is to mount an auxiliary printed circuit board subassembly including capacitors, typically surface mount capacitors, on the electrical connector. Although there have been a number of prior art connectors of this general type, many of these prior art connectors have been relatively expensive to produce. There remains a need for filtered electrical connectors that use inexpensive components and standard assembly techniques so that the connector can be cost effectively produced.
Some electrical connectors employ a printed circuit board mounted to the connector housing. Discrete surface mount chip components are soldered to traces on this printed circuit board extending between a ground and the contact terminals soldered or press fit in through holes in the printed circuit board. Examples of such connectors are disclosed in U.S. Pat. No. 4,729,752 and in copending U.S. Pat. No. application Ser. No. 08/355,767 (Attorney's Docket. No. 16048) filed Dec. 12, 1994, which application is assigned to the assignee hereof.
Another approach to positioning surface mount capacitors in a connector is shown in U.S. Pat. No. 5,152,699 where the capacitors are positioned in depressions in a housing above or below plug pins. A ground plate having bent plate portions is located adjacent these depressions and is sandwiched between the housing sections. The capacitors can be soldered to the pins and to the bent out plate sections of the ground plate.
One approach to manufacturing filtered electrical connectors of this type has been to use standard chip components in standard Electronic Industries Association (EIA) packages, such as EIA 0603, EIA 0805 and EIA 1206 surface mount capacitors that are spring loaded in the connector. An example of the use of chip components urged by a spring into contact with a corresponding terminal are found in U.S. Pat. No. 5,151,054; U.S. Pat. No. 5,152,699; and U.S. Pat. No. 5,344,342. In U.S. Pat. No. 5,151,054 separate spring fingers are stamped in two plates located on either side of a two row electrical connector. In U.S. Pat. No. 5,152,699 fingers on a metal plate urge components into engagement with contact terminals. In U.S. Pat. No. 5,344,342 a metal ground plate includes a plurality of fingers on a ground spring that bias capacitors against signal contacts. This ground plate, spring, or clip is located along one side of the housing and the ground clip must include a ground tail that can be soldered to a ground contact in the connector. Apparently multiple ground plates must be used with multirow electrical connectors with this type of configuration.
Another approach is to solder a standard surface mount capacitor to a metal plate and to provide a spring on the plate to engage the contact terminals. One such approach is shown in U.S. Pat. No. application Ser. No. 08/401,594 (Attorney's Docket No. 16050) filed Mar 9, 1995, in the name of Gary R. Marpoe.
U.S. Pat. No. 5,340,335 shows another approach in which a compressible resilient conductive member is positioned in engagement with a surface mount chip component. The preferred embodiment of that compressible member is an elastomeric connector including an elastomeric core surrounded by a polyimide film with contact paths on the film. Products of this type are manufactured and sold by AMP Incorporated under the trademark AMPLIFLEX, which is a trademark of The Whitaker Corporation. The contact terminals are mounted in a printed circuit board, or similar substrate, and the chip component is biased into engagement with pads on the same printed circuit board by the compressible member. The compressible member also engages a flat surface of a ground plate or a shroud. Although this connector is suitable for such applications it does require the use of a number of parts including a printed circuit board. The compressible elastomeric connector also engages a flat ground plate. In order to insure adequate contact force, the thickness of this ground plate must be sufficient to prevent bowing or the width of the ground plate and connector must be limited. This connector also requires that the capacitors or similar chip components must be loaded endwise into passageways that extend between opposite faces of the connector housing. This endwise loading is not the typical way in which components are mounted on printed circuit boards using typical assembly techniques. Components of this type are normally mounted on their sides on printed circuit boards and conventional component assembly techniques handle the components in this manner.
The other prior art described herein and known to applicant also requires extra parts to assemble the components in the connector housing or unconventional assembly techniques. Extra assembly operations are thus required and additional manufacturing dies and molds are also required. Any additional step or part adds cost to the electrical connector and should be avoided if possible.
The instant invention eliminates both assembly techniques, such as soldering, and the use of printed circuit boards. This invention also makes use of such standard assembly techniques as pick and place insertion techniques that are desirable when assembling a large number of electrical connectors and handling a large number of electrical components, e.g., surface mount chip capacitors. Only simple dies are needed to manufacture the shields and ground plates employed with this invention and in some cases existing shields can be employed. No costly molds with core pins forming bores through molded housings are needed and thin housing walls are not required. Manufacturing operations are thereof not adversely affected by core pin breakage, and the incidence of defective molded parts caused by failure to fill the wall sections during injection molding operations is also reduced. This invention is also suitable for use with connectors having a large number of contacts since there is no tendency for the ground plate to bow near the center of long contact rows.